Dead subreddits, dead forums and abandoned meetups might disagree with that assessment. Building a community is far from easy and there's a lot of effort involved to keep it going as an organizer or moderator. Setting it up initially is easy, keeping it going for many years is hard.

I've set up, moderated forums, irc servers and organized a regular meetup for many years and I've seen that all the time.

You might be kind of young, so there was this time when "Facebook for health" and "amazon for X" were used as legitimate pitch items as a way to frame the potential of whatever CRUD app someone was selling as a billion dollar visionary idea. It was very tiring. The modern equivalent is something like a "DALL-E 0llamma MLA is all you need" post about a random arvix article about ML

That's not how I read it at all.. It's the "HN for..." part that is the sense of grandeur.. Not the idea of self-hosting vs. using Reddit or Discord.

HN has been around for 15 years, it has earned its place as a quality community through time and much effort (i.e. moderation).

So to call yourself "HN for..." as a brand new thing is like opening up a brand new coffee shop in your town and saying "we're the next Starbucks"...

What if such feeling is justified? Everything else equal, I'd rather have a community not belong to Reddit, and I'd be horrified if HN somehow "migrated" to being a sub, the difference between communities is enormous.